Add Fedora instructions and Repology badge

`rbw` is now available in Fedora and EPEL 9. Document the installation.

Also future-proof by listing all distros and versions known to Repology.

See also https://github.com/repology/repology-rules/pull/829/files for
merging the related `rbw` and `rust:rbw` listing - the Fedora package
and the `crates.io` upload will be merged into `rbw` when the PR goes
in.

Signed-off-by: Michel Lind <[email protected]>

README.md

@@ -21,6 +21,8 @@ and merge pull requests implementing those features.
 
 ## Installation
 
+[![Packaging status](https://repology.org/badge/vertical-allrepos/rbw.svg?exclude_unsupported=1)](https://repology.org/project/rbw/versions)
+
 ### Arch Linux
 
 `rbw` is available in the [extra
@@ -37,6 +39,13 @@ You can download a Debian package from
 [`minisign`](https://github.com/jedisct1/minisign), and can be verified using
 the public key `RWTM0AZ5RpROOfAIWx1HvYQ6pw1+FKwN6526UFTKNImP/Hz3ynCFst3r`.
 
+### Fedora/EPEL
+
+`rbw` is available in [Fedora and EPEL 9](https://bodhi.fedoraproject.org/updates/?packages=rust-rbw)
+(for RHEL and compatible distributions).
+
+You can install it using `sudo dnf install rbw`.
+
 ### Homebrew
 
 `rbw` is available in the [Homebrew repository](https://formulae.brew.sh/formula/rbw). You can install it via `brew install rbw`.